Flux cored electrode

ABSTRACT

A continuous welding electrode for shielded-gas welding and building-up of steels consisting of 25 to 35 percent by weight of a powdery core in a steel envelope, the core consisting of the following components taken in per cent by weight: RUTILE CONCENTRATE20-40FERROMANGANESE10-13FELDSPAR0.6-6.0SODIUM FLUOROSILICATE0.6-4.6FERROSILICON0.6-2.0 THE BALANCE BEING IRON POWDER.

ilnited States Patent 1 i olthodnya et al.

[451 May 15, 1973 [54] FLUX CORED ELECTRODE [22] Filed: July 8,1971

[21] Appl. No.: 160,920

52 U.S.Cl ..2l9/146,2 19/137 51 Int. Cl ..'.Bf23k 35 22 [58] Field ofSearch ....,.2l9/l45, 146, 73, 219/137; 117/202-207; 148/24, 26

[56] 1 References Cited UNITED STATES PATENTS 3,221,136 11/1965 Freethetal. ..1 17/205 X Primary ExaminerJ. V. Truhe we e" w ehfiw e A; MqvaAttorney-Eric H. Waters et al.

[57] ABSTRACT A continuous welding electrode for shielded-gas weldingand building-up of steels consisting of 25 to 35 percent by weight of apowdery core in a steel envelope, the core consisting of the followingcomponents taken in per cent by weight:

rutile concentrate 20-40 ferror'nanganese 10- 1 3 feldspar 0.6-6.0sodium fluosilicate 0.6-4.6 ferrosilicon the balance being iron powder 71 Claim, No Drawings FLUX CORED ELECTRODE The present invention relatesto electrode materials for electric-arc welding and, more particularly,the invention relates to continuous electrodes for shieldedgas weldingand building-up of metals.

This invention can be most effectively used in the process of automaticand semi-automatic welding at downhand, inclined, and horizontalposition of the weld joints on a vertical plane.

Known in the art are continuous flux-cored electrodes for shielded-gaswelding These electrodes contain a powdery core. The electrodes having acore containing titanium dioxide and silica feature the best weldingcharacteristics among the known electrodes for shielded-gas welding andbuilding-up.

For example, a continuous flux-cored electrode is known the core ofwhich contains 4-40 percent of deoxidizing ferroalloys, 75-96 percent ofslag producing compounds, including 60-85 percent of titanium dioxide,8-25 percent of silica, 4-20 percent of manganese oxides.

These known flux-cored electrodes, however, do not provide for highquality of the metal of the weld joint: when a metal covered with rustand scale is welded, the weld joint features a porous structure; theefficiency of the building-up is low.

The specific object of the invention is to develop such a continuouselectrode for welding and buildingup of metals in a shielding gasmedium, the composition of the core of which would provide for goodwelding-and-technological characteristics and mechanical properties ofthe welded metal within a wide range of operating conditions, a highefficiency of the building-up process, and absence of pores in the weldjoints on metal covered with rust and scale.

This object is attained by providing such a continuous electrode forshielded-gas welding and building-up of steels (preferably in anatmosphere of CO which consists of a powdery core in a steel envelopecomprising rutile concentrate and ferromanganese, wherein, according tothe invention, the powdery core, besides the above components taken inthe following percentages by weight:

rutile concentrate 20 40 ferromanganese 10 13,

comprises:

feldspar 0.6 6.0

sodium fluosilicate 0.6 4.6

ferrosilicon 0.6 2.0,

the balance being iron powder.

The continuous electrode having a core composition according to theinvention has fine welding-and-technological characteristics andprovides for a high quality of the weld joint metal during the welding.The weld joints made by means of such an electrode offer high resistanceto formation of hot cracks and pores.

The present invention will be better understood from the followingexamples of carrying out the invention into effect.

The proposed continuous electrode for shielded-gas welding andbuilding-up consists of a powdery core in a steel envelope comprisingthe following components (per cent by weight of the core):

The balance being iron pzwder being the rest.

The selected ratio of the core components makes it possible to obtainslag having good physical characteristics.

The presence of sodium fluosilicate in the core sharply reduces thecontent of gases in the weld joint metal without deteriorating thetechnological characteristics of the electrode.

The sodium fluosilicate may be replaced by fluorite concentrate.However, in this case the content of fluorite concentrate in theelectrode core must be equal to 4-6 percent. However, in this case thewelding-and-technological characteristics of the electrode aredrastically deteriorated and this is associated with poor formation ofthe weld joints, and intensive splashing of the electrode metal. Toimprove the transfer of the electrode metal, the electrode core shouldbe provided with oxides of alkaline earth metals. But any increase inthe oxidizing potential of the core is associated with deterioration ofthe mechanical properties of weld joint metal and formation of hotcracks in the weld joint.

The advantage of the proposed continuous welding electrode compared withthe known electrodes is illustrated by the following examples whereinthe weight of the core is in the range of 25 to 35 percent of the weightof the electrode.

Example 1 A continuous welding electrode having a diameter of 2 mm, inwhich the steel envelope comprises 75 percent of the total weight of theelectrode, while the core contains the following components, percent byweight:

Rutile concenuate 2O Ferromanganese 10 Feldspar 0.6 Sodium fluosilicate0.6 Ferrosilicon 0.6 Iron powder 68.2

provides for good formation of fillet and butt joints. The electrodeensures high mechanical characteristics of the metal of the weld joint.

Impact strength, InstantakgmJcrnfl at tem- Are neous Specific perature,0. Welding voltage, strength, elongation, current, a. v. kgJmm. percent+20 Example 2 A continuous welding electrode of a diameter of 2.5

mm in which the steel envelope comprises percent of the total weight ofthe electrode and the core contains the following components, percent byweight:

Rutile concentrate 28.8 Ferroman 11.6 Feldspar 3.3 Sodium fluoeilicate1.6 Ferrosilicon 1.0 lron powder 54.0

provides for extreme good formation of a weld joint when effecting thewelding at downhand and inclined positions. The weld joints offer goodresistance to cracks and pores. The mechanical properties of the weldjoint metal and the weld joint are at a high level as is seen from thedata given below.

Impact strength,

InstantakgJem. at tem- Arc neous Specific perature, 0. Welding voltage,strength, elongation, current, a. v lrgJmm. percent +20 -60 Example 3 Iv A continuous welding electrode having a diameter of 3.0 mm in whichthe steel envelope comprises 65 percent of the total weight of theelectrode and the core contains the following components, percent byweight:

Rutile concentrate 40 Ferromanganese l 3.0 Feldspar 6.0 Sodiumfluosilicate 4.6 Ferrosilicon 2.0 lron powder 34.4

Impact strength, lnstentakgJcni. at. turn- Are neous Specific peruture,(J. Welding voltage, strength, elongation, current, a. v. kg./mm.percent +20 above examples clearly illustrate the advantages of theproposed continuous welding electrode.

The proposed electrode makes it possible to effect the welding by director alternating current, ensures extremely good formation of the weldjoints, while providing for easy removal of the slag crust.

The efficiency of thebuilding-up is up to 15 kg/hour. The splash of theelectrode metal is completely eliminated. The welds made by means of theproposed electrode have extremely high mechanical characteristics andoffer high resistance to formation of hot cracks. The electrode makes itpossible to weld rusty and scaly metal.

We claim: 7

l. A continuous welding electrode for shielded-gas welding andbuilding-up of steels said electrode consisting of 25 to 35 percent byweight of a powdery core and 75 to percent by weight of a steelenvelope, said core consisting of the following components in per centby weight:

rutile concentrate 2O 40 ferromanganese l0 l3 feldspar 0.6 6.0 sodiumfluosilicate 0.6 4.6 ferrosilicon 0.6 2.0

the balance being iron powder.

